by (Click here to view) This article about suspended ceilings (Frequency Sensitivity of the seismic damage to suspended ceilings, doi: 10.1002/eqe.
3861), the initial idea also originated from the 7.0 magnitude earthquake in Lushan, Sichuan, exactly ten years ago.
The focus on seismic damage of non structural components also began there.
One of the concerns is the extensive destruction of suspended ceilings in public buildings.
In addition to taking photos to describe the phenomenon, we also paid attention to collecting some quantitative data, such as the drop rate of ceiling panels of similar types: that is, a whole piece of ceiling, regardless of size, how many percent of the ceiling panels fell during the earthquake.
We collected 20 samples of suspended ceilings from different buildings, and the situation of 16 samples with a drop rate of less than 100% is shown in the following figure.
It is not enough to only know the degree of damage (referred to as the rate of falling plates here), and it is also necessary to know the degree of damage they occur under what earthquake action.
It is generally believed that the degree of damage to a suspended ceiling depends on the magnitude of the peak floor acceleration (PFA).
So we attempted to invert the peak ground acceleration (PGA) of these buildings, and estimated the PFA of the building on the floor where the overhead crane is located.
Then, we obtained the following graph.
Emmmmm The linear correlation coefficient between the ceiling drop rate and PFA is only 0.375.
Is PFA so bad? Of course, the PFA used here is not measured, but only estimated and may not be accurate.
Later, one day, in an article by Grandpa Nakajima introducing q-NAVI, I accidentally saw the relationship between the actual damage to suspended ceilings in Japanese buildings and the measured PFA.
It is not that the larger the PFA, the easier the suspended ceiling is to break.
So we decided to design a test to check whether PFA is the final the final say for the damage of the ceiling.
This is not a big deal either, but when we decided to conduct this experiment, our planet had already orbited its star five times since the 2013 Lushan earthquake.
Considering the potential for significant discreteness in the suspended ceiling panels, we have decided to cut a minimum element containing various main components (main keel, secondary keel, suspended ceiling panel, suspension wire) from the ordinary public ceiling as the research object.
This way, you can go to Yanjiao’s 5 × Place four identical suspended ceiling test specimens simultaneously on the vibration table of 5.
The loading method also has ulterior motives“
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